Purpose:
Variability exists regarding assessing the mobility functional performance for patients with tunnel vision. We performed observational clinical study for validating a new design of an indoor mobility course that is easy to assemble in a variety of settings. This course is proposed to be used in assessing mobility functional performance for patients with tunnel vision.

Methods:
Seventy participants recruited in this study, twenty of them suffered from advanced tunnel vision due to retinitis pigmentosa (TVPs) and the remaining were normally-sighted participants (SIPs) where we simulated the tunnel vision using four goggles. All of them were asked to walk twice along a 14 metre indoor corridor containing 16 obstacles, once in each direction. The visual acuity, contrast sensitivity and visual field were measured. The SIPs repeated the test on a second occasion but not the TVPs as they were part of a larger clinical study. In each case the time taken to complete the course was expressed as the percentage preferred walking speed (PPWS) and the number of collisions was recorded.

Results:
The binocular field of view (FoV) of all the participants ranged from 4° to 22°. For the SIPs, the PPWS and the collision scores both showed a significant relationship to FoV on both visits; for PPWS: r = 0.58; r = 0.56; p <0.0001, respectively; for collisions: r = -0.50, r = -0.55, p < 0.0001, respectively. Generally, no significant difference was found between the mobility scores between visits. The FoV of the TVPs was significantly related to their PPWS scores, r = 0.40, p = 0.04. No significant relationship was found between the TVPs FoV and collision scores. A significant relationship was found between the TVPs’ VA and collisions (r = 0.40, p = 0.03).

Conclusions:
Our results suggested that this design is valid and sensitive and could be a useful tool for assessing mobility functional performance in tunnel vision patients. This mobility course is shorter than most of previous designs, therefore, does not require dedicated space and could be replicated easily in other studies and in a variety of setting. The course could be a useful tool for assessing functional performance in tunnel vision patients.